Meanwhile this fascinating Politico piece went inside the war on coal, sharing how Sierra Club activists have targeted coal in particular—allying themselves with, and sometimes accepting money from, natural gas companies and advocates with quite spectacular results. (The Sierra Club's Beyond Coal initiative has since pledged to stop accepting money from the natural gas industry.)

For those who have been following this space for some time, this is hardly news. The world was always going to go through a transition period in which fossil fuels are still an important piece of the energy puzzle—and going after the dirtiest fuels like coal and tar sands first may be a pretty smart strategy. (Although natural gas is hardly a carbon-free fuel itself.)

As an activist friend of mine commented the other day, these decisions are as hard as they are important for committed environmentalists. I can't think of many greenies I know who are keen to see fracking wells proliferate, and yet we can't deny the fact that cheap natural gas is playing a central role in undermining coal. The important thing, I think, is to keep an eye on the end game and to remember that temporary alliances and/or shared common goals are not the same thing as permanent allegiance. (The Sierra Club continues to campaign on issues such as fracking, even as it plays gas off against coal in other quarters.)

And let's not forget that once our electric utilities have set themselves a firm path away from coal, the game changes once again—because Big Oil (and probably gas) come next. Here's how Bruce Nilles of Sierra Club's Beyond Coal campaign put it in the Politico piece:

“Once we’ve taken out coal, we’ll need to take on oil, and who better to help than our new friends in the utility sector who can make money from electrification?” Nilles says with a grin. “It’s a long fight. This is how we win.”